five-year study of off-road vehicles, complemented by separate social science and ornithological studies, resulted in the development of an off-road vehicle management plan that was instituted after public review and comment. The plan allows vehicular access to some of the better surf fishing areas while protecting dunes, vegetation, and shore birds, including the piping plover, and minimizes conflicts between different types of uses at swimming beaches. The plan, based on careful scientific studies, has withstood challenges in a U.S. District Court.
The Devil's Hole pupfish, endemic in a single undisturbed pool in Death Valley National Monument in California, has a smaller range than any other North American vertebrate. A decline in water levels began in 1968 when groundwater pumping for agricultural irrigation began on adjacent private lands. Scientific studies revealed that reproduction necessary to sustain the endangered species could only occur if the water level in the pool was high enough to support growth of algae on a shallow rock shelf within the pool. With this knowledge, the NPS mitigated the problem by purchasing certain adjacent lands to protect against groundwater overdraft and obtaining a permanent court order that prevents pumping of groundwater that lowers the water level below the rock shelf. The court order, which was based on scientific research, was upheld by the U.S. Supreme Court.
The protection of Everglades National Park in Florida seemed at first glance assured by the setting aside of some one million acres in south Florida, a total since increased by the creation of Big Cypress National Preserve adjacent to the national park. However, the park boundaries did not encompass all of the areas that proved critical to the functioning of park ecosystems, and the effects of land use and water management outside the park soon became evident. Today the park faces a variety of serious problems related to water levels and water flow patterns, agricultural pollutants, exotic species, and habitat destruction. One result is that the population of wading birds has declined more than 90 percent since the 1930s, from about 250,000 in 1934 to 7,800 today. The population of endangered wood storks has declined from 5,000 birds in 1956 to 375 birds today.